Evaluation of the peroxynitrite scavenging activity of heat-processed ginseng.

To ascertain the principal active peroxynitrite (ONOO(-)) scavenging components of heat-processed Panax ginseng C.A. Meyer (sun ginseng [SG]), the ONOO(-) scavenging activities of fractions and components of SG were compared. The results demonstrated that the ONOO(-) scavenging ability of SG was due to its ether fraction containing phenolic compounds. High-performance liquid chromatography analysis and ONOO(-) scavenging activity tests of the phenolic acids contained in SG identified vanillic acid, ferulic acid, p-coumaric acid, syringic acid, and maltol as the main active ONOO(-) scavenging components of SG. The ONOO(-) scavenging activities of phenolic acids and maltol were dependent on the degrees of their proton donating ability.

Effect of sun ginseng methanol extract on lipopolysaccharide-induced liver injury in rats.

Sun ginseng (SG) is heat-processed Panax ginseng C.A. Meyer steamed at 120 degrees C, which has ginsenoside-Rg(3), -Rk(1), and -Rg(5) as its main ginsenoside components. The effect of SG on lipopolysaccharide (LPS)-induced liver injury in rats was investigated in this study. Intravenous injection of LPS induced excessive nitric oxide (*NO) generation in serum and increased the hepatic mitochondrial thiobarbituric acid-reactive substance (TBA-RS) level. However, the elevated TBA-RS level was significantly lowered by 15 consecutive days of SG administrations. In addition, up-regulated hepatic inducible nitric oxide synthase and heme oxygenase 1 levels in LPS-treated control rats were significantly lowered and increased, respectively, by 100 mg/kg body weight/day of SG administration. These antioxidant effects were thought to be partially related to the deactivation of nuclear factor-kappaB by SG administration.

Therapeutic potential of heat-processed Panax ginseng with respect to oxidative tissue damage.

Panax ginseng has been reported to exhibit a wide range of pharmacological and physiological actions. A method of heat-processing to enhance the efficacy of ginseng is well established in South Korea based on a long history of ethnopharmacological evidence. We investigated the increase in free radical-scavenging activity of Panax ginseng as a result of heat-processing and its active compounds related to fortified antioxidant activity. In addition, the therapeutic potential of heat-processed ginseng (HPG) with respect to oxidative tissue damage was examined using rat models. Based upon chemical and biological activity tests, the free radical-scavenging active components such as less-polar ginsenosides and maltol in Panax ginseng significantly increased depending on the temperature of heat-processing. According to animal experiments related to oxidative tissue damage, HPG displayed hepatoprotective action by reducing the elevated thiobarbituric acid reactive substance (TBA-RS) level, as well as nuclear factor-kappa B (NF-kappaB) and inducible nitric oxide synthase (iNOS) protein expressions, while increasing heme oxygenase-1 in the lipopolysaccharide-treated rat liver, and HPG also displayed renal protective action by ameliorating physiological abnormalities and reducing elevated TBA-RS, advanced glycation endproduct (AGE) levels, NF-kappaB, cyclooxygenase-2, iNOS, 3-nitrotyrosine, N?-(carboxymethyl)lysine, and receptors for AGE protein expression in the diabetic rat kidney. Therefore, HPG clearly has a therapeutic potential with respect to oxidative tissue damage by inhibiting protein expression related to oxidative stress and AGEs, and further investigations of active compounds are underway. This investigation of specified bioactive constituents is important for the development of scientific ginseng-derived drugs as part of ethnomedicine.

Amla (Emblica officinalis Gaertn.) extracts reduce oxidative stress in streptozotocin-induced diabetic rats.

The antioxidant properties of amla extracts and their effects on the oxidative stress in streptozotocin-induced diabetes were examined in rats. Amla in the form of either the commercial enzymatic extract SunAmla (Taiyo Kagaku Co. Ltd., Yokkaichi, Japan) (20 or 40 mg/kg of body weight/day) or a polyphenol-rich fraction of ethyl acetate extract (10 or 20 mg/kg of body weight/day) was given orally for 20 days to the streptozotocin-induced diabetic rats. Amla extracts showed strong free radical scavenging activity. Amla also showed strong inhibition of the production of advanced glycosylated end products. The oral administration of amla extracts to the diabetic rats slightly improved body weight gain and also significantly alleviated various oxidative stress indices of the serum of the diabetic rats. The elevated serum levels of 5-hydroxymethylfurfural, which is a glycosylated protein that is an indicator of oxidative stress, were significantly reduced dose-dependently in the diabetic rats fed amla. Similarly, the serum level of creatinine, yet another oxidative stress parameter, was also reduced. Furthermore, thiobarbituric acid-reactive substances levels were significantly reduced with amla, indicating a reduction in lipid peroxidation. In addition, the decreased albumin levels in the diabetic rats were significantly improved with amla. Amla also significantly improved the serum adiponectin levels. These results form the scientific basis supporting the efficacy of amla for relieving the oxidative stress and improving glucose metabolism in diabetes.

The role of Coptidis Rhizoma extract in a renal ischemia-reperfusion model.

The effect of Coptidis Rhizoma extract on ischemia-reperfusion in rats was examined. The blood levels of urea nitrogen and creatinine increased significantly more in rats subjected to 24-h reperfusion than those subjected to 6-h reperfusion following 1-h ischemia, indicating functional kidney damage was more severe after the longer reperfusion time. These parameters were reduced by oral administration of Coptidis Rhizoma extract. Greater activity was found in rats given the extract for 30 days than in rats given the extract for 10 days prior to ischemia-reperfusion. In addition, the serum malondialdehyde level was lower, while the glutathione/glutathione disulfide ratio and the activities of the antioxidation enzymes, superoxide dismutase and catalase, were higher in rats given Coptidis Rhizoma extract orally for 30 consecutive days prior to 1-h ischemia and 24-h reperfusion in comparison with control rats given water. These results indicate that Coptidis Rhizoma has a protective action against the renal dysfunction caused by the ischemia and reperfusion process. Furthermore, renal DNA of rats given Coptidis Rhizoma extract orally showed a significantly lower DNA fragmentation rate, which was dose-dependent, implying that the extract afforded the kidneys protection against oxidative stress-mediated apoptosis during the process and ameliorated renal function impairment.

Effect of Wen-Pi-Tang extract on lung damage by influenza virus infection.

The effect of Wen-Pi-Tang extract on influenza virus infection in mice was investigated. The administration of Wen-Pi-Tang extract at a dose of 100mg/kg body wt. for 8 consecutive days to influenza virus-infected mice reversed the lack of body wt. gain and prevented the increase in lung weight caused by the infection in comparison with uninfected mice, while allopurinol, a xanthine oxidase (XOD) inhibitor, did not show these effects. The serum levels of uric acid and allantoin in influenza virus-infected mice were reduced by Wen-Pi-Tang extract administration. Moreover, Wen-Pi-Tang extract reduced the uric acid level more as the dose increased, although it exerted lower activity than allopurinol. The XOD activity of the lungs was elevated by influenza virus infection, but Wen-Pi-Tang extract administration inhibited this activity, indicating prevention of lung damage by oxygen free radicals generated by XOD. After the administration of Wen-Pi-Tang extract to influenza virus-infected mice, the lung superoxide dismutase activity was not significantly different from that of uninfected mice, whereas lung catalase activity was lower in the former than the latter, but slightly higher than that of influenza virus-infected mice, suggesting that Wen-Pi-Tang extract may prevent the generation of highly toxic hydroxyl radicals in the lung. In addition, the administration of both Wen-Pi-Tang extract and allopurinol reduced the degree of lung consolidation caused by influenza virus infection. In particular, Wen-Pi-Tang extract reduced the consolidation score in a dose-dependent manner and more markedly than allopurinol did. This study suggests that Wen-Pi-Tang extract could improve pathological conditions of the lungs induced by influenza virus infection.

Study on the inhibitory effects of Korean medicinal plants and their main compounds on the 1,1-diphenyl-2-picrylhydrazyl radical.

A 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-generating system was used to evaluate the antioxidant properties of Korean medicinal plants that have been used widely as folk medicines for several disorders, as well as compounds isolated from them. Among the Rosaceae, Rosa rugosa and Rosa davurica showed strong DPPH radical-scavenging activity. The most effective medicinal plant from families other than Rosaceae was Cedrela sinensis, followed in order by Nelumbo nucifera, Eucommia ulmoides, Zanthoxylum piperitum, Cudrania tricuspidata and Houttuynia cordata. These results serve as a good index of the free radical-scavenging activities of Korean medicinal plants. Furthermore, the polyphenols isolated from these plants, procyanidin B-3, (+)-catechin, gallic acid, methyl gallate, quercetin, quercetin-3-O-beta-D-glucoside, quercetin-3-O-beta-galactoside, quercetin-3-O-rutinose and kaempferol, exerted strong DPPH radical-scavenging activity. These results suggest that the Korean medicinal plants and the polyphenols isolated from them that exhibited effective radical-scavenging activity may be promising agents for scavenging free radicals and treating diseases associated with excess free radicals.

Cyclooxygenase-2 expression in thyroid neoplasms.

AIMS: Previous studies have demonstrated that cyclooxygenase-2 (COX-2) plays a role in carcinogenesis and carcinoma development. In this study, we investigated its expression in thyroid neoplasms in order to elucidate its role. METHODS AND RESULTS: COX-2 expression was studied immunohistochemically in 20 anaplastic (undifferentiated) carcinomas, 49 papillary carcinomas, 22 follicular carcinomas and 15 follicular adenomas. Positive staining was only occasionally seen in normal follicles or stromal cells. COX-2 over-expression was found in only 20.0% of follicular adenomas and 40.9% of follicular carcinomas. In papillary carcinomas, the incidence (81.3%) was significantly higher (P < 0.0001) than in follicular carcinomas, although COX-2 expression was reduced in cases with old age (P = 0.0190), large size (P = 0.0028), advanced stage (P = 0.0225), satellite tumours (P = 0.0363), and the presence of solid, scirrhous or trabecular growth patterns (P = 0.0018). Undifferentiated carcinomas less frequently over-expressed COX-2 (P = 0.0004), with an incidence of 40.0%. CONCLUSIONS: These results indicate that the up-regulation of COX-2 may contribute predominantly in the early phase of papillary carcinoma progression, whereas it plays a more adjuvant role in follicular carcinoma progression.

The effects of Coptidis Rhizoma extract on a hypercholesterolemic animal model.

The serum cholesterol (total, free, esterified, low density lipoprotein (LDL) and oxidized LDL) levels of rats fed a diet containing, by weight, 1% cholesterol and 0.5% cholic acid increased, as compared with those of rats fed a normal diet. The levels, especially of total cholesterol, LDL and oxidized LDL, were reduced significantly in a dose-dependent manner, in rats given Coptidis Rhizoma extract orally at doses of 50 and 100 mg/kg body wt./day for 30 days. These results indicate that Coptidis Rhizoma extract is effective in reducing the pathological damage caused by hypercholesterolemia, through lowering of serum cholesterol levels. In addition, Coptidis Rhizoma extract reduced the level of liver cholesterol, but it did not reduce that of fecal cholesterol, suggesting that the cholesterol level-lowering effect resulted from the reduction of cholesterol synthesis, not the enhancement of its excretion. Furthermore, the serum thiobarbituric acid-reactive substance level decreased after oral administration of Coptidis Rhizoma extract, indicating that Coptidis Rhizoma could prevent hypercholesterolemic disease through reducing lipid peroxidation. This study demonstrates that Coptidis Rhizoma may be a useful therapy for hypercholesterolemia through reducing oxidative stress and cholesterol levels.

Direct scavenging of nitric oxide and superoxide by green tea.

In the present study, we investigated the free radical scavenging effects of green tea extract and green tea tannin mixture and its components using a nitric oxide (NO) and superoxide (O(2)(-)) generating system in vitro. Green tea extract showed direct scavenging activity against NO and O(2)(-) and green tea tannin mixture, at the same concentration, showed high scavenging activity. Comparison of the activities of seven pure compounds isolated from green tea tannin mixture showed that (-)-epigallocatechin 3-O-gallate (EGCg), (-)-gallocatechin 3-O-gallate (GCg) and (-)-epicatechin 3-O-gallate (ECg) had higher scavenging activities than (-)-epigallocatechin (EGC), (+)-gallocatechin (GC), (-)-epicatechin (EC) and (+)-catechin (C), showing the importance of the structure of flavan-3-ol linked to gallic acid for this activity. Among the gallate-free tannins, EGC and GC were more effective O(2)(-) scavengers than EC and C, indicating the O-trihydroxy structure in the B ring is an important determinant of such activity. However, this structure did not affect the NO scavenging activity. These findings confirm that green tea tannin has excellent antioxidant properties, which may be involved in the beneficial effect of this compound.

Examination of the nitric oxide production-suppressing component in Tinospora tuberculata.

The component of aqueous Tinospora tuberculata extract that inhibits nitric oxide (NO) production was examined using macrophages activated by the addition of lipopolysaccharide. The aqueous extract was partitioned with ethyl acetate. The aqueous layer was fractionated with a Diaion column. The residue of the aqueous extract was extracted with methanol, and partitioned with ethyl acetate. The ethyl acetate layer was found to be associated with a distinct decrease in the NO level and inducible NO synthase. On further fractionation, the subfraction of E-3 showed high anti-NO activity. N-trans-Feruloyltyramine isolated from E-3 was identified as exhibiting strong anti-NO activity. This compound is the most active component of Tinospora tuberculata with respect to the suppression of NO production.

Effects of buckwheat in a renal ischemia-reperfusion model.

Experiments were done to find whether buckwheat extract ameliorates the renal injury induced by ischemia-reperfusion. In ischemic-reperfused control rats, the activities of antioxidative enzymes in renal tissue and blood and renal parameters deviated from the normal range, indicating dysfunction of the kidneys. In contrast, when buckwheat extract was given orally for 20 consecutive days before ischemia and reperfusion, the activities of the antioxidation enzymes superoxide dismutase, catalase, and glutathione peroxidase were higher, while thiobarbituric acid-reactive substance levels in serum and renal tissue were lower in the treated rats than in the controls. Decreased levels of urea nitrogen and creatinine in serum demonstrated a protective effect against the renal dysfunction caused by ischemia and recirculation. On the other hand, it was demonstrated that buckwheat extract had a protective effect on cultured proximal tubule cells subjected to hypoxia-reoxygenation, probably by preventing oxygen free radicals from attacking the cell membranes.

Effects of hokoei-to (pugongying-tang), a Kampo formula, on monoamine content in brain regions and mitogenic activity of splenic lymphocytes in ovariectomized mice.

Hokoei-to (pugongying-tang) is one of the Kampo formulae clinically used for gynecological disturbances such as lack of lactation and mammary swelling. We investigated the effect of hokoei-to on the nervous and immune systems in ovariectomized mice as a climacteric disorder model. Hokoei-to suppressed the decrease of monoamines in the ventral hippocampus and dorsal hippocampus of ovariectomized mice. It was shown that the hokoei-to could improve the metabolic turnover of dopamine. The mitogenic activity of lymphocytes in the spleen was reduced after ovariectomy; a suppression of this reduced activity was observed in the group given hokoei-to.

Inhibitory effects of an aqueous extract of Apocynum venetum leaves and its constituents on Cu(2+)-induced oxidative modification of low density lipoprotein.

An aqueous extract of Apocynum venetum leaves and its constituents inhibited thiobarbituric acid reactive substances (TBARS) and conjugated-diene formation in the Cu(2+)-induced oxidation of low density lipoprotein (LDL) in vitro. The TBARS formation was most strongly inhibited by chlorogenic acid with an IC(50) value of 1.9 microM, but other constituents were in a range of 2.3-23.3 microM. On the other hand, the lag time in the conjugated-diene formation was dose-dependently prolonged by addition of the aqueous extract. Catechin prolonged the lag time more than 300 min and other constituents such as chlorogenic acid, epicatechin, epigallocatechin, hyperoside and isoquercitrin led to no conjugated-diene formation within 700 min under the experimental conditions.

Antioxidative activity of green tea treated with radical initiator 2, 2'-azobis(2-amidinopropane) dihydrochloride.

This study investigated the antioxidative activity of green tea extract, and a green tea tannin mixture and its components, under conditions of radical generation using the hydrophilic azo compound, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) to generate peroxyl radicals at a constant and measurable rate in the cultured renal epithelial cell line, LLC-PK(1), which is susceptible to oxidative damage. Treatment with AAPH decreased cell viability and increased the formation of thiobarbituric acid-reactive substances. However, green tea extract, and the tannin mixture and its components, comprising (-)-epigallocatechin 3-O-gallate (EGCg), (-)-gallocatechin 3-O-gallate (GCg), (-)-epicatechin 3-O-gallate (ECg), (-)-epigallocatechin (EGC), (+)-gallocatechin (GC), (-)-epicatechin (EC), and (+)-catechin (C), showed protective activity against AAPH-induced cellular damage. The tannin mixture and its components exhibited higher antioxidative activity than the green tea extract. Furthermore, EGCg and GCg had higher activity than EGC and GC, respectively. In particular, EGCg exerted the most significant cellular protective activity against AAPH. These results indicate that green tea tannin may inhibit cellular loss and lipid peroxidation resulting from the peroxyl radical generated by AAPH, and that the chemical structure of tannin is also involved in the activity, suggesting that the O-dihydroxy structure in the B ring and the galloyl groups are important determinants for radical scavenging and antioxidative potential.

Effects of aqueous extracts of Apocynum venetum leaves on spontaneously hypertensive, renal hypertensive and NaCl-fed-hypertensive rats.

Effects of aqueous extracts of Apocynum venetum leaves (Luobuma extracts) on the blood pressure were evaluated in hypertensive animal models, such as spontaneously hypertensive rats (SHR), renal hypertensive rats and NaCl-induced hypertensive rats. In SHR, administration of Luobuma (heat-processed and unprocessed leaves) extracts at a dose of 70 mg/rat per day significantly decreased the systolic blood pressure value, but their decreasing effects were weaker than that of captopril. The urine volume, and the urinary Na(+), K(+) and protein excretions were not significantly different between Luobuma-treated and untreated groups. In 3/4 nephrectomized rats, the Luobuma extracts significantly decreased the systolic blood pressure value, accompanied by significant increases of the urine volume and the urinary Na(+) and K(+) excretions. Furthermore, they decreased the blood urea nitrogen (BUN) level. In NaCl-induced hypertensive rats, the Luobuma extract decreased the systolic blood pressure value. However, it did not change the urinary excretions of Na(+), K(+) and protein. The BUN level was lower than that of control rats, but the serum total cholesterol (TC) level did not changed. From these findings, the Luobuma extracts have an anti-hypertensive effect, possibly due to amelioration of the kidney functions in the three experimental animal models.

A study on the nitric oxide production-suppressing activity of sanguisorbae radix components.

The active components of an aqueous extract of Sanguisorbae Radix, which possesses nitric oxide (NO) production-suppressing activity, were determined using macrophages that were activated by the addition of lipopolysaccharide. Significant inhibitory activity against the formation of both NO and inducible NO synthase, and NADPH-diaphorase activity, which is involved in NO generation, was shown by Sanguisorbae Radix fractions T-B and T-C. On further fractionation, the subfractions of T-B and T-C all showed high anti-NO activity. Sanguiin H-6, sanguiin H-11, 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, eugeniin and polymeric proanthocyanidin were isolated from TB-3 and TC-4, and all were identified as exhibiting strong anti-NO activity. We have confirmed that sanguiin H-6 is the most active component of Sanguisorbae Radix with respect to the suppression of NO production. It is suggested that tannin makes a prominent contribution to the biological activity of Sanguisorbae Radix.

The role of ginsenoside-Rd in cisplatin-induced acute renal failure.

Ginsenoside-Rd has been proved to decrease the severity of renal injury induced by cisplatin, in which proximal urinaferous tubules represent the main site of injury. When ginsenoside-Rd was given orally at a dose of 1 or 5 mg/kg body weight/day for 30 consecutive days prior to cisplatin injection, the activities of the antioxidation enzymes superoxide dismutase and catalase were higher, while malondialdehyde levels in serum and renal tissue were lower in the treated rats than in the controls. The levels of urea nitrogen and creatinine in serum were decreased in rats given ginsenoside-Rd. Decreased urinary levels of glucose, sodium and potassium reflected a protective action against the renal dysfunction caused by cisplatin. In addition, it was demonstrated that ginsenoside-Rd affected cultured proximal tubule cells exposed to cisplatin.

Role of Salviae Miltiorrhizae Radix extract and its compounds in enhancing nitric oxide expression.

Excessive production of nitric oxide (NO) and its peroxidant product, peroxynitrite, has been implicated in the pathology of acute and chronic renal failure, and inhibitors of NO production have been shown to exert protective and ameliorative effects against renal epithelial cell damage mediated by enhanced generation of NO. Salviae Miltiorrhizae Radix has exhibited a beneficial effect in the improvement of renal failure. In order to clarify the mechanism responsible, we investigated whether Salviae Miltiorrhizae Radix extract and several of its related compounds, including caffeic acid and its polymers which were isolated by our research group, can regulate the generation and release of NO. The results demonstrated that Salviae Miltiorrhizae Radix extract and these compounds suppressed NO effectively in the systems employing activated macrophages and the arginine-hydrogen peroxide, and that, furthermore, the activity shown by the compounds was higher than that shown by the extract. In addition, direct scavenging of NO was also observed. The present findings suggest that Salviae Miltiorrhizae Radix extract and its compounds are potent NO inhibitors, and that their inhibitory effect on the generation and release of NO may contribute to the previously reported pharmacological effect of Salviae Miltiorrhizae Radix in improving renal function.

Protective effects of Glycyrrhizae radix extract and its compounds in a renal hypoxia (ischemia)-reoxygenation (reperfusion) model.

Glycyrrhizae radix water extract (GRWE) and its two major constituents glycyrrhizin and 3-glycyrrhetinic monodesmoside, significantly suppressed LDH leakage and MDA release, whereas glycyrrhetinic acid had no effect. On the other hand, in rats subjected to ischemia-reperfusion, the activities of endogenous antioxidant enzymes including catalase and glutathione peroxidase showed recovery, whereas the levels of urea nitrogen and creatinine in serum were reduced by administration of glycyrrhizin orally for 30 days prior to ischemia-reperfusion. These results indicate that GRWE and its two constituents may be promising for amelioration of hypoxia (ischemia)-reoxygenation (reperfusion) injury and improvement of renal function by acting directly or indirectly as antioxidant and oxygen radical-scavenging agents.